Ed Kilgore is right–and when isn’t he?–that National Review’s Ramesh Ponnuru makes a pretty good case for why conservatives should support Mitt Romney. But this seems to be a bit fanciful and is leaving out a key fact:

Romney cannot win in November 2012, [his conservative critics] say, because conservative voters will lack the motivation to cast ballots for someone so uninspiring and moderate. Thomas Sowell and George Will are among the conservative heavyweights who have made this case recently, with Sowell noting pointedly that the conservative Reagan won two presidential elections where moderates such as Bob Dole and John McCain have lost them.

Yet George W. Bush won two elections, albeit close ones, with positions to Romney’s left and rhetoric that attempted to distance him from the bulk of conservatives. (He was the compassionate one, you may recall.) The truth is that Republicans have never lost a presidential election because an otherwise viable nominee could not get conservatives to vote. The exit polls from the 2008 election show that the race was lost in the center of the electorate. If Romney is anywhere near Obama in the polls in October 2012, conservative voters will show up to help him. To win, though, he will also need some votes from people who voted for Obama in 2008 — and he has a much better chance of getting them than his rivals do. [Emphasis added]

Let’s set aside the case of Bush, who didn’t win the 2000 election despite getting to run a stealth campaign that mollified movement conservatives while trading on his parents’ generally high favorability and deceiving a gullible press with nostrums about compassionate conservativism. Let’s look at McCain.

I remember John McCain, and Mitt Romney is no John McCain. McCain was a veteran and a war hero, had a national reputation as a “maverick” and a long and fairly consistent conservative voting record. Mitt Romney not only lacks these political assets, he also has the liabilities of being viewed–much more so than the also-wealthy McCain–as too wealthy to understand most Americans, of being associated with a religious faith that a decent-sized minority of Americans admit they distrust, of being associated with passing a health-care program in Massachusetts that conservatives hate and is remarkably like what Obama signed in to law on a national level, and of being a flip-flopper.

Despite those comparative advantages, McCain had his own liabilities, in particular with movement conservatives. He was never comfortable or believable as a zealous culture warrior, Right to Life and the National Rifle Association hated the campaign finance law he passed with Russ Feingold, and his occasional apostasies on taxes and earmarks undermined his standing with the anti-tax wing of the Republican party.

Ponnunu is correct to point out that conservatives still came out and voted for McCain. But he fails to note one big reason why. After he secured the nomination McCain’s team was worried that conservatives would stay home. McCain wanted to pick a VP like former Pennsylvania governor Tom Ridge, but Ridge is pro-choice so it was a non-starter. You know the rest: to drum up support with the conservative base, McCain picked Sarah Palin. Enthusiasm among conservatives did indeed go up, as demonstrated at Palin rallies where crowds shouted out death threats to Barack Obama and Palin accused him of cavorting with terrorists.

McCain himself appeared taken aback at the hateful vitriol spewed against Obama. But it did help gin up enthusiasm with the Republican base, that mostly loved Palin. The problem, of course, was that in fixing his problem with the Republican base, McCain almost certainly hurt himself with independent voters.

As I said, Ponnuru makes a pretty good case for Romney, who probably is the most electable Republican in the field. But if he’s going to explain how Romney–more distrusted by conservatives than McCain ever was–will rally the Republican base, Ponnuru should probably explain how Romney can rally the base without antagonizing independents and moderates.

McCain needed Palin to get conservatives to vote. Romney is less liked and trusted by conservatives than McCain, so he’ll probably need his version of Palin. But it’s hard to imagine Romney finding a Palin-like way to motivate his base without the corresponding Palin-like damage to his standing with the other voters he would need to win.